Preservation of cell cycle characteristics in solid tumor in vitro.

Cell cycle parameters of explanted solid tumor (renal carcinoma HKC-400) were analyzed by short-term incubation in vitro and compared with those measured in the animal. The tissue fragments were labeled with [3H]thymidine under hyperbaric oxygen. Continuous labeling index increased linearly at the same rate as in the in vivo experiment, and the S-phase length by this method coincided with that obtained by the fraction of labeled mitoses method. Duration of G2 + M phases was measured from the continuously labeled mitoses curve and was found to agree with the in vivo data. These results indicated that cell cycle progression was not blocked in vitro at least for a limited time after explanation, and possible clinical application of this technique ws discussed.